Snowmobile Arctic Cat (2007 year). Manual - part 15

2-45

2

741-617B

„ NOTE: If removing the oil cooler for cleaning pur-
poses, remove the union bolt securing the cooler
to the engine; then remove the oil cooler and
account for a washer and an O-ring.

ZJ040

18. Remove the Allen-head cap screws securing the

right-side and left-side timing chain tension

guides to the engine; then remove the guides and

account for the timing chain and the washers

located between the tension guides and engine.

ZJ041A

19. Remove the fourteen cap screws securing the oil

pan to the engine; then remove the oil pan and

note the location of the different-length cap

screws for assembling purposes.

741-584B

20. Tip the engine upside down; then remove the 28

cap screws securing the upper and lower crank-

case halves. Using a soft hammer, gently tap

around the bottom half until it separates.

„ NOTE: Note the location of the different-length
cap screws for assembling purposes.

21. After separating the crankcase halves, account

for two O-rings (A) and dowel pins.

ZJ042A

22. For easier access to components, rotate the

crankshaft to the bottom-dead-center position

(connecting rod caps straight up).

„ NOTE: For assembling purposes, note the align-
ment marks on the crankshaft and on the crank
balancer gears. The rear marks are double dots
(A), and the front marks are single dots (B).

! CAUTION

DO NOT drive any tool between halves to separate
the crankcase. Damage to the sealing surfaces will
result.

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ZJ068A

23. Remove the front and rear crank balancers from

the engine and account for the two end seals.

ZJ043

24. On each connecting rod, remove the two con-

necting rod cap screws; then remove the con-

necting rod cap. Account for the two connecting

rod bearings.

ZJ052B

„ NOTE: Because the connecting rods and con-
necting rod caps are unique, it is recommended
that the technician take note of the I.D. marks and
keep all associated parts together for assembling
purposes.

25. With the connecting rod caps removed, thread

the cap screws into the rods; then using a soft

hammer, gently tap the piston assembly out the

top side of the cylinder.

ZJ044

„ NOTE: For assembling purposes, note that the
dot on the piston dome is directed toward the
exhaust side of the engine.

ZJ045A

26. Carefully remove the crankshaft from the

engine; then account for the PTO-side end seal,

the two thrust bearings, and three bearing

halves.

ZJ053

„ NOTE: For assembling purposes, note that the
oil grooves of the thrust bearings face the counter-
weights of the crankshaft.

! CAUTION

Pistons can be removed from the top side of the cyl-
inder only.

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2

ZJ046A

27. Remove the oil separator plates for the lower

crankcase half and account for the eight Allen-

head cap screws.

ZJ047A

28. Remove the Allen-head cap screws securing the

piston cooling jets to the upper crankcase half;

then remove the jets and account for the O-

rings.

ZJ054A

ZJ035

„ NOTE: For assembling purposes, ensure that the
orifices in the piston cooling jets are cleared of
any dirt and/or debris.

ZJ055A

Servicing Components

(120 cc)

„ NOTE: Critical engine specifications are located
at the beginning of this section.

Thoroughly clean all non-electrical components in

parts-cleaning solvent; then remove any carbon

buildup from the cylinder head, piston dome,

valves, and valve seats.

Visually inspect all engine components for wear or

damage.

„ NOTE: Whenever a part is worn excessively,
cracked, or damaged in any way, replacement is
necessary.

CYLINDER HEAD/VALVE 
ASSEMBLY

„ NOTE: Remove the valves by pressing down on
the spring retainer and removing the valve keeper.
Account for valve springs, spring retainers, and
valve keepers.

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When servicing valve assembly, inspect valve seats,

valve stems, valve faces, and valve stem ends for

pits, burn marks, or other signs of abnormal wear.

„ NOTE: Discard any valve that fails the listed
inspections. Do not grind the valves. If a valve is
damaged, it must be replaced.

Measuring Cylinder Head 

Distortion

1. Using a non-metallic carbon removal tool,

remove any carbon buildup from the combus-

tion chambers being careful not to nick, scrape,

or damage the combustion chambers or the seal-

ing surfaces.

2. Inspect the spark-plug holes for any damaged

threads. Repair damaged threads using a heli-

coil insert.

3. Inspect the cylinder head for flatness using a

straightedge and a feeler gauge. Acceptable dis-

tortion must not exceed specifications.

„ NOTE: If the distortion exceeds specification,
replace the cylinder head.

Measuring Valve Stem Runout

1. Support each valve stem end with V Blocks (p/n

0644-022); then check the valve stem runout

using a dial indicator.

ATV-1082

2. Maximum runout must not exceed specifica-

tions for both valves.

Measuring Valve Face Width

1. Using a micrometer, measure the width of the

valve face.

ATV-1004

2. Acceptable valve face width must be within

specifications.

Measuring Valve Face Runout

1. Mount a dial indicator on a surface plate; then

place the valve stem on a set of V blocks.

2. Position the dial indicator contact point on the

outside edge of the valve face; then zero the

indicator.

ATV1082A

3. Rotate the valve in the V blocks.

4. Maximum runout must not exceed specifica-

tions.

Replacing Valve Guide

„

NOTE: If a valve guide is worn or damaged, it

must be replaced.

1. If a valve guide needs replacing, before remov-

ing the existing guide, measure the distance

from the top of the valve seat to the top of the

valve guide (B) for a reference depth when

installing the new guide.